1. Field of the Invention
The present invention relates generally to computer cursor control devices, and more particularly to methods and apparatus for establishing tactile feedback in a cursor control device based on an associated computer's displayed graphical presentation.
2. Description of the Related Art
The immense rise in popularity of personal computers is in large part attributable to improvements in user-machine interfaces. More particularly, the improvements in data input devices, such as the mouse and the trackball, have made communication with computers easy and convenient, thus increasing the usefulness of computers.
As is well-known, a mouse and a trackball are useful devices for positioning a cursor on a computer display. To quickly and efficiently input certain types of data or commands to a computer, the cursor is positioned on an appropriate graphics object and then manipulated (colloquially referred to as "clicked"). It will readily be appreciated that the convenience and, thus, usefulness of the computer is promoted by facilitating rapid, yet precise, cursor placement.
Representative of such cursor control devices is the device sold under the trademark "Trackpoint" by International Business Machines Corporation of Armonk, N.Y., the assignee of the present invention. Details of the "Trackpoint" device are disclosed in related U.S. patent applications Ser. Nos. 07/917,091 and 08/006,427, both of which are assigned to International Business Machines Corporation and incorporated herein by reference.
It happens, unfortunately, that rapid cursor positioning is more or less competitive with precise cursor positioning. This is because the faster the cursor moves across the screen, the less time the user has to react to stop the cursor when it arrives at the desired screen location. Stated differently, the user is provided with only one kind of feedback, namely, visual feedback, to aid the user in stopping a rapidly moving cursor, and visual feedback alone often is insufficient to promote both rapid and precise cursor placement.
As the present invention recognizes, however, both rapid and precise cursor placement can be enhanced if more than one kind of feedback is provided to the user. More specifically, the present invention recognizes that tactile feedback can be used in conjunction with visual feedback to promote both rapid and precise cursor placement.
As still further recognized herein, while tactile feedback can be effective for its intended purpose, providing a tactile feedback signal every time a cursor crosses a semantic boundary can be somewhat distracting, thereby detracting from the advantages provided by the device. Accordingly, the present invention recognizes that the effectiveness of tactile feedback in a cursor control device can be promoted by rendering tactile feedback only upon certain predetermined conditions.
It is therefore an object of the present invention to provide a cursor control system that generates a tactile feedback signal to a user when a cursor controlled by the system crosses a graphics boundary. Another object of the present invention is to provide a cursor control system that generates a tactile feedback signal only when a cursor crosses a tactile boundary defined to be "interesting". Still another object of the present invention is to provide a cursor control system that generates a tactile feedback signal in part based on the speed of the cursor. Yet another object of the present invention is to provide a cursor control system that generates a tactile feedback signal in part based on the time since a tactile feedback signal was last generated. Another object of the present invention is to provide a cursor control system that is easy to use and cost-effective.